Any gardener that has ever grown potatoes knows that it’s easy to miss a potato or two in the harvesting process. Then, come springtime, we discover that we have a few volunteer potato plants growing from the tubers that got left behind.
This led me to wonder if potatoes can come back year after year without the hassle of having to replant every season. Here’s what I’ve learned.
Even though a few volunteer potatoes may come up in the spring, it doesn’t mean that potatoes will continue to come back every year. It’s best to replant your garden with new seed potatoes every spring.
I’ll share more info on why it’s best to plant a fresh potato crop every year and what may happen if you choose to leave your tubers in the ground over winter.
Are potatoes perennial plants?
Contrary to popular belief, potatoes are perennial. This means that they can reproduce year after year without having to be replanted. But, this isn’t how potatoes are commonly grown.
Most of us grow potatoes as an annual crop meaning we have to plant fresh seed potatoes every year to get a new crop.
You’re probably wondering then why most people grow potatoes as an annual if it’s technically a perennial.
Well, although the greens may come back year after year, there’s no guarantee that you will continue to get the big tubers you’re looking for. You may not get any tubers at all.
Potatoes left in the ground for the next season may start to crowd one another as they send up new shoots and start producing new tubers. This can lead to competition for water and nutrients, especially because potatoes are heavy feeders.
Lifecycle of a potato plant
For most of us, the life of our potato plants starts in the spring with the planting of the first seed potatoes. Shortly after planting, potatoes will start to grow sprouts from their eyes.
The eyes of potatoes look like small dimples on the outside of a tuber, sometimes with a small nub connected to it. This dimple or nub is the beginning of a potato sprout.
Sometimes potatoes have tiny sprouts even before being planted. Don’t be alarmed if you see sprouts starting to form on your seed potatoes before you’ve even put them in the ground. They’re supposed to do this!
After about 3 weeks from planting, the leaves of the potato plant will begin to emerge from the ground. The new tubers are also beginning to develop at this time.
Eventually, the potato plant will reach a point where it stops growing greens to focus its energy on tuber growth. During this time, the plants may form some flowers but this doesn’t always happen. Flowers are not necessary for healthy tuber growth.
After about 90 to 110 days, potato plants will reach full maturity. At this point, the leaves may begin to yellow and will start to die back.
Once the leaves have begun to die back, your potatoes should be ready for harvest. They should be harvested sooner rather than later to help prevent rot in the tubers. But, they can be left in the ground for up to 2 weeks to help cure the potatoes for storage.
Can you leave potatoes in the ground over winter?
Potatoes can overwinter in the ground, meaning they can go dormant as a way to survive the colder temps. But, when they start growing again in the spring, the plants may be less than ideal for tuber growth.
Potatoes that are left in the ground long after their harvest time run the risk of rotting in the ground and turning to mush. This will lead to poor tuber growth in the next season if the rotten potatoes send up new shoots at all.
This is much more likely to happen in wetter climates or in regions where the soil freezes in the winter. Once the soil freezes completely, it is also much more difficult to dig your tubers out of the ground and can end up harming your soil.
And, as I mentioned earlier, the overwintered tubers that do send up new shoots in the spring will be very close to one another and start to compete for space and nutrients. This can leave you with really small potatoes that don’t last that long in storage.
Storing potatoes in a garden trench
Sometimes, people like to build garden trenches in the ground as a storage method for potatoes. This is different than simply leaving them in the ground unharvested because garden trenches provide insulation to keep the tubers from freezing.
To successfully make a garden trench, you’ll want to dig a spot about 2 feet deep and wide enough that you’re able to spread your potatoes out in one even layer.
Once your trench is dug, lay down a good thick layer of straw for insulation. Then you can place your tubers in the trench. After your tubers are evenly layered, go ahead and cover them with another layer of straw. You shouldn’t be able to see the potatoes.
A note on experimenting
Although I’ve just written about all of the reasons why you shouldn’t grow potatoes as perennials, I’d hate for that to deter any adventurous gardeners who may want to experiment with alternative potato-growing methods.
If getting a large potato harvest isn’t your end goal, then maybe try leaving some potatoes in the ground over winter and see what happens in the spring.
Every garden is different for so many different reasons. Maybe your garden holds the key to growing perennial potatoes.
Although potatoes are technically perennials, it’s best to grow them as annuals every year to ensure a good harvest. Leaving potatoes in the ground overwinter with the hopes that they’ll produce new plants in the spring can be very hit or miss.
Tubers left in the ground over winter run the risk of rotting and not producing anything in the spring. They can also start to crowd each other underground and compete for space and nutrients.
Of course, if you have the space in your garden, maybe you experiment with growing potatoes as perennials. If that turns out fruitful, definitely let us at Tiny Garden Habit know so we can try it too!